JPH0667376B2 - Flexible tube for endoscope - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flexible tube of an endoscope used for observing the inside of a living body cavity or the inside of a machine, and in particular,
The present invention relates to a flexible tube having improved durability by improving the outer cover made of synthetic resin that constitutes the flexible tube.

[Prior Art] In the flexible tube of an endoscope, generally, the outer circumference of a spiral tube is covered with a mesh tube braided with fine metal wires, and the outer circumference is covered with a flexible outer shell made of synthetic resin. The conventional
The thickness t of the outer skin is 0 with respect to the outer diameter dimension D of the flexible tube.
It was in the range of 03D <t <0.04D.

[Problems to be Solved by the Invention] A flexible tube of an endoscope is used while being repeatedly bent with a small radius of curvature in a living body cavity or the like. Therefore, the flexible tube is required to have sufficient durability against bending so as not to be damaged by buckling due to bending.

However, when the flexible tube of the conventional endoscope is repeatedly bent with a small radius of curvature, as shown in FIG. 3, wrinkles s occur in the outer skin b portion inside the curve, and the flexible tube buckles. , As a result, for example, the optical fiber bundle, the electric wire or the forceps channel or other tubes inserted in the flexible tube may be damaged, or the curved portion may not be sufficiently buckled, There was a drawback that the mirror became unusable.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the conventional drawbacks described above, and to provide a flexible endoscope tube that does not buckle even when repeatedly bent and has excellent durability.

[Means for Solving the Problems] In order to solve the above problems, the inventor found through experiments that durability against bending is closely related to the thickness of the outer skin of the flexible tube. As will be described in detail in the section of Examples below, when the thickness t of the outer skin is within the range of t <0.04D with respect to the outer diameter dimension D of the flexible tube, wrinkles occur and the flexible tube buckles. It is possible that wrinkles do not occur if t ≧ 0.04D.

On the other hand, the flexible tube of the endoscope to be inserted into the living body cavity has an outer diameter dimension D in order to alleviate the pain to the patient.
Is desirable to be thin, even if it is small. This is a well-known fact, and the wall thickness t of the outer skin of the flexible tube should not be unduly increased. It is not necessary that t ≧ 0.05 even in consideration of technical problems such as dimensional variations in mass production, and by setting t <0.05D, it is possible to suppress the pain to a patient to a certain level or less.

Therefore, the flexible tube of the endoscope according to the present invention will be described with reference to FIG. 1 corresponding to the embodiment. The outer circumference of the spiral tube 11 is covered with a mesh tube 12 braided with fine metal wires, and the outer circumference is further synthesized. Flexible outer skin 13 made of resin
In the flexible tube 1 of the endoscope which is coated with
Thickness t is 0.04D ≦ t with respect to the outer diameter dimension D of the flexible tube 1.
It is characterized by being in the range of <0.05D.

[Operation] Even if the flexible tube is repeatedly bent with a small radius of curvature, the outer tube does not wrinkle and the flexible tube does not buckle.

[Embodiment 1] A first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

Reference numeral 1 denotes an insertion portion flexible tube to be inserted into a living body cavity or the like. An operation portion 2 provided with various operation devices is connected to a proximal end of the insertion portion flexible tube 1, and the operation portion is provided at a distal end. A bending portion 3 that is freely bent by remote control from 2 is connected, and a tip forming portion 4 having an objective optical system and the like built therein is attached to the tip thereof.

5 is a connector connected to a light source device (not shown),
The connector 5 and the operating portion 2 are connected by a connecting flexible tube 6.

The insertion portion flexible tube 1 has a mesh tube 12 formed by braiding a metal thin wire such as a stainless steel wire on the outer circumference of a spiral tube 11 made of a metal band such as a copper alloy or a stainless steel band. The outer periphery is covered with an outer cover 13 made of, for example, a polyurethane resin or a polyolefin resin by a method such as extrusion molding.

Similarly to the insertion portion flexible tube 1, the connecting flexible tube 6 is also formed by coating the outer circumference of the spiral tube 61 with the mesh tube 62 and further covering the outer circumference thereof with the outer cover 63.

FIG. 2 is a cross-sectional view of the flexible tube 1 of the insertion section. An optical fiber bundle, forceps channels and other tubes are inserted into the flexible tube 1 of the insertion section, but not shown. There is.

In the present embodiment, the outer diameter D of the insertion portion flexible tube 1 is 16 mm, and the durability test in which the flexible tube is repeatedly bent with a small radius of curvature by changing the wall thickness t of the outer cover 13 variously. I did. The results are shown below.

The spiral tube 11 was made of copper alloy, the reticulated tube 12 was made of stainless steel wire, and the outer skin 13 was made of both polyurethane resin and polyolefin resin. No significant difference was found in the results. The hardness of the resin was equivalent to JIS rubber hardness of 75 ^{± 10} degrees.

Outer skin thickness result t = 0.55mm (0.034D): Wrinkles t = 0.60mm (0.038D): Rare wrinkles t = 0.65mm (0.041D): No wrinkles t = 0.70mm (0.044D): No wrinkles t = 0.80mm (0.050D): No wrinkles t = 0.90mm (0.056D): No wrinkles t = 1.00mm (0.063D): No wrinkles (D = 16mm) Example 2] The outer diameter D of the flexible tube 1 is set to 12 mm, the other conditions are the same as in the first embodiment, the thickness t of the outer skin 13 is variously changed, and the flexible tube is repeated with a small radius of curvature. A bending durability test was performed.

Outer skin thickness result t = 0.40mm (0.033D): Wrinkles t = 0.45mm (0.038D): Rare wrinkles t = 0.50mm (0.042D): No wrinkles t = 0.55mm (0.046D): No wrinkles t = 0.60mm (0.050D): No wrinkles t = 0.65mm (0.054D): No wrinkles t = 0.75mm (0.063D): No wrinkles (D = 12mm) Example 3] The outer diameter D of the insertion portion flexible tube 1 is 6 mm, and the resin hardness is
JIS rubber hardness was set to 85 ^{± 10} degrees, other conditions were changed to the thickness t of the outer skin 13 in the same manner as in Example 1, and an endurance test of repeatedly bending the flexible tube with a small radius of curvature was performed.

Outer skin thickness result t = 0.20mm (0.033D): Wrinkles t = 0.25mm (0.042D): No wrinkles t = 0.30mm (0.050D): No wrinkles t = 0.35mm (0.058D): No wrinkles t = 0.40 mm (0.067D): No wrinkles (D = 6 mm) [Example 4] Outer diameter D of the insertion portion flexible tube 1 is 2 mm, and resin hardness is
JIS rubber hardness was set to 85 ^{± 10} degrees, other conditions were changed to the thickness t of the outer skin 13 in the same manner as in Example 1, and an endurance test of repeatedly bending the flexible tube with a small radius of curvature was performed.

Outer skin thickness result t = 0.07mm (0.035D): Wrinkles t = 0.08mm (0.040D): No wrinkles t = 0.09mm (0.045D): No wrinkles t = 0.10mm (0.050D): No wrinkles t = 0.12 mm (0.060D): No wrinkles (D = 2 mm) In the above-described embodiments, the present invention is applied to the insertion portion flexible tube 1.
However, it may be applied to the connecting flexible tube 6.

EFFECTS OF THE INVENTION According to the flexible tube of the endoscope of the present invention, the thickness t of the outer skin is set to t ≧ 0.04D with respect to the outer diameter D of the flexible tube, so that the flexible tube has a small curvature. Even if it is repeatedly bent at a radius, the flexible tube will not buckle and durability will be greatly improved. Also, since t <0.05D, the pain to the patient into which the flexible tube is inserted is limited to a certain level or less, and if the wall thickness t has a width of about 0.04D ≦ t <0.05D, it can be mass-produced. Are suitable.

[Brief description of drawings]

FIG. 1 is a view in which a part of an embodiment of the present invention is cut away, and FIG.
The drawing is a sectional view of the flexible tube taken along the line II-II, and FIG. 3 is a view showing a state in which the flexible tube has wrinkles. 1 ... Insertion part flexible tube, 11 ... Spiral tube, 12 ... Mesh tube, 13 ... Outer skin

Claims (2)

[Claims] 1. An endoscope having an outer diameter of less than 6 mm in which a spiral tube is braided with fine metal wires and the outer circumference of the spiral tube is covered with a flexible outer shell made of synthetic resin. In the flexible tube, the thickness t of the outer skin is 0 with respect to the outer diameter dimension D of the flexible tube.
A flexible tube for an endoscope, which is in the range of 04D ≦ t <0.05D. 2. The flexible tube for an endoscope according to claim 1, wherein the outer cover is made of polyurethane resin or polyolefin resin.